1. Field
This invention relates to telephone switching technology and computer networking technology, more particularly to telephone and internetworking systems that use digital signal processors to handle calls.
2. Background
Some telephone systems use digital signal processors (DSPs) to handle and switch calls between incoming and outgoing digital phone calls and an Integrated Digital Services Network (ISDN). In one example, these processors are contained on a card or circuit board referred to as a MICA, Modem ISDN Channel Aggregation. Some MICA cards are organized to handle several calls per module and contain several modules. A typical example would be a card having 10 modules, each of which can handle 6 modem calls. Typically, each module will contain several DSPs.
A problem occurs when the firmware in the DSP needs to be upgraded. In order to do this, no calls can be active on the module. Typically, the upgrade is performed after all of the active calls have hung up, or all the active calls are terminated. The first option is not much of a problem when there are only 6 calls per module. It can be problematic, but still feasible when there are 12 calls. However, future generations of the modules envision 30 and 60 calls per module, with even more expanded capability in sight. In view of the high number of calls that might be occurring on each module, waiting for a time when there are no active calls might be next to impossible.
Similarly, actively terminating calls on a module to perform the upgrade may not be a solution. With only 6 calls possible to be active, it is possible to terminate the calls and only cause 6 to 12 disgruntled customers. However, disappointing 30 or 60 customers is not really a feasible alternative.
Additionally, a typical access server may contain several modules. Waiting for one of the above events to occur for each module would require a lengthy period of time to complete the upgrade. The longer it takes to wait between modules, the longer the overall upgrade will take.
A method and apparatus that would allow upgrades to be performed without waiting would be useful.